(Power Bank NOT INCLUDED). 【How to use】Take out the USB plug ,connect the power bank (Output should be 5V, 2A/2.1A.). 1PC 9-zone heating vest. USB Port: USB connector Port at the pocket. Button function: USB interface at the pocket, power on and long press the switch button for on/off; short press is to adjust the gear; on the red light slightly flashing is directly heated to high temperature preheating.
eBay